Browse
Submit Data
Databases
API
Help

Dataset Information

23 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Selective electrochemical reduction of nitric oxide to hydroxylamine by atomically dispersed iron catalyst.

ABSTRACT: Electrocatalytic conversion of nitrogen oxides to value-added chemicals is a promising strategy for mitigating the human-caused unbalance of the global nitrogen-cycle, but controlling product selectivity remains a great challenge. Here we show iron-nitrogen-doped carbon as an efficient and durable electrocatalyst for selective nitric oxide reduction into hydroxylamine. Using in operando spectroscopic techniques, the catalytic site is identified as isolated ferrous moieties, at which the rate for hydroxylamine production increases in a super-Nernstian way upon pH decrease. Computational multiscale modelling attributes the origin of unconventional pH dependence to the redox active (non-innocent) property of NO. This makes the rate-limiting NO adsorbate state more sensitive to surface charge which varies with the pH-dependent overpotential. Guided by these fundamental insights, we achieve a Faradaic efficiency of 71% and an unprecedented production rate of 215 μmol cm^-2 h^-1 at a short-circuit mode in a flow-type fuel cell without significant catalytic deactivation over 50 h operation.

SUBMITTER: Kim DH

PROVIDER: S-EPMC7994811 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Tuning selectivity of electrochemical reactions by atomically dispersed platinum catalyst.

Project description:Maximum atom efficiency as well as distinct chemoselectivity is expected for electrocatalysis on atomically dispersed (or single site) metal centres, but its realization remains challenging so far, because carbon, as the most widely used electrocatalyst support, cannot effectively stabilize them. Here we report that a sulfur-doped zeolite-templated carbon, simultaneously exhibiting large sulfur content (17 wt% S), as well as a unique carbon structure (that is, highly curved three-dimensional networks of graphene nanoribbons), can stabilize a relatively high loading of platinum (5 wt%) in the form of highly dispersed species including site isolated atoms. In the oxygen reduction reaction, this catalyst does not follow a conventional four-electron pathway producing H2O, but selectively produces H2O2 even over extended times without significant degradation of the activity. Thus, this approach constitutes a potentially promising route for producing important fine chemical H2O2, and also offers opportunities for tuning the selectivity of other electrochemical reactions on various metal catalysts.

| S-EPMC4786782 | biostudies-literature

Atomically Dispersed Pentacoordinated-Zirconium Catalyst with Axial Oxygen Ligand for Oxygen Reduction Reaction.

Project description:Single-atom catalysts (SACs), as promising alternatives to Pt-based catalysts, suffer from the limited choice of center metals and low single-atom loading. Here, we report a pentacoordinated Zr-based SAC with nontrivial axial O ligands (denoted O-Zr-N-C) for oxygen reduction reaction (ORR). The O ligand downshifts the d-band center of Zr and confers Zr sites with stable local structure and proper adsorption capability for intermediates. Consequently, the ORR performance of O-Zr-N-C prominently surpasses that of commercial Pt/C, achieving a half-wave potential of 0.91 V vs. reversible hydrogen electrode and outstanding durability (92 % current retention after 130-hour operation). Moreover, the Zr site shows good resistance towards aggregation, enabling the synthesis of Zr-based SAC with high loading (9.1 wt%). With the high-loading catalyst, the zinc-air battery (ZAB) delivers a record-high power density of 324 mW cm-2 among those of SAC-based ZABs.

| S-EPMC9543759 | biostudies-literature

Selective hydrogenolysis of catechyl lignin into propenylcatechol over an atomically dispersed ruthenium catalyst.

Project description:C-lignin is a homo-biopolymer, being made up of caffeyl alcohol exclusively. There is significant interest in developing efficient and selective catalyst for depolymerization of C-lignin, as it represents an ideal feedstock for producing catechol derivatives. Here we report an atomically dispersed Ru catalyst, which can serve as an efficient catalyst for the hydrogenolysis of C-lignin via the cleavage of C-O bonds in benzodioxane linkages, giving catechols in high yields with TONs up to 345. A unique selectivity to propenylcatechol (77%) is obtained, which is otherwise hard to achieve, because this catalyst is capable of hydrogenolysis rather than hydrogenation. This catalyst also demonstrates good reusability in C-lignin depolymerization. Detailed investigations by model compounds concluded that the pathways involving dehydration and/or dehydrogenation reactions are incompatible routes; we deduced that caffeyl alcohol generated via concurrent C-O bonds cleavage of benzodioxane unit may act as an intermediate in the C-lignin hydrogenolysis. Current demonstration validates that atomically dispersed metals can not only catalyze small molecules reactions, but also drive the transformation of abundant and renewable biopolymer.

| S-EPMC7814062 | biostudies-literature

Selective and Sensocompatible Electrochemical Nitric Oxide Sensor with a Bilaminar Design.

Project description:Macrophages mediate mammalian inflammation in part by the release of the gasotransmitter, nitric oxide (NO). Electrochemical methods represent the best means of direct, continuous measurement of NO, but monitoring continuous release from immunostimulated macrophages remains analytically challenging. Long release durations necessitate consistent sensor performance (i.e., sensitivity and selectivity for NO) in proteinaceous media. Herein, we describe the fabrication of an electrochemical sensor modified by an electropolymerized 5-amino-1-naphthol (poly(5A1N)) film in conjunction with a fluorinated xerogel topcoat. The unique combination of these membranes ensures selective detection of NO that is maintained over extended periods of use (>24 h) in biological media without performance deterioration. The hydrophobic xerogel topcoat protects the underlying NO-selective poly(5A1N) film from hydration-induced desorption. The bilaminar sensor is then readily adapted for measurement of the temporal NO-release profiles from immunostimulated macrophages.

| S-EPMC6759084 | biostudies-literature

Regeneration of the Waste Selective Catalytic Reduction Denitrification Catalyst by Nitric Acid Washing.

Project description:In this study, the waste V2O5-WO3/TiO2 denitrification catalysts from the coal-fired power plant were washed with water or nitric acid, followed by impregnating different contents of V2O5. The effects of the HNO3 concentration and the additional amount of vanadium on the low-temperature selective catalytic reduction denitrification activity were investigated under the condition of high concentration of SO2 and H2O. The catalysts were characterized by inductively coupled plasma optical emission spectrometry, X-ray powder diffraction , N2 adsorption/desorption, H2-temperature-programmed reduction, NH3-temperature-programmed desorption , Fourier transform infrared spectroscopy , and Raman spectroscopy. The evaluation results revealed that optimum activity was achieved by using 0.8 mol/L HNO3 solution and loading 1.60 wt % V2O5 to make the total V2O5 reach 2.3 wt %. The characterization results showed that nitric washing can remove most of the ammonium salts deposited on the surface of the waste catalyst and produce crystalline WO3, which can effectively inhibit the agglomeration of vanadium species in the process of impregnation. Furthermore, it can also increase the amount of oligomeric VO x , which can improve the denitration activity.

| S-EPMC6788065 | biostudies-literature

Iced photochemical reduction to synthesize atomically dispersed metals by suppressing nanocrystal growth.

Project description:Photochemical solution-phase reactions have been widely applied for the syntheses of nanocrystals. In particular, tuning of the nucleation and growth of solids has been a major area of focus. Here we demonstrate a facile approach to generate atomically dispersed platinum via photochemical reduction of frozen chloroplatinic acid solution using ultraviolet light. Using this iced-photochemical reduction, the aggregation of atoms is prevented, and single atoms are successfully stabilized. The platinum atoms are deposited on various substrates, including mesoporous carbon, graphene, carbon nanotubes, titanium dioxide nanoparticles, and zinc oxide nanowires. The atomically dispersed platinum on mesoporous carbon exhibits efficient catalytic activity for the electrochemical hydrogen evolution reaction, with an overpotential of only 65?mV at a current density of 100?mA?cm-2 and long-time durability (>10?h), superior to state-of-the-art platinum/carbon. This iced-photochemical reduction may be extended to other single atoms, for example gold and silver, as demonstrated in this study.

| S-EPMC5684195 | biostudies-literature

Atomically dispersed cobalt catalyst anchored on nitrogen-doped carbon nanosheets for lithium-oxygen batteries.

Project description:Developing single-site catalysts featuring maximum atom utilization efficiency is urgently desired to improve oxidation-reduction efficiency and cycling capability of lithium-oxygen batteries. Here, we report a green method to synthesize isolated cobalt atoms embedded ultrathin nitrogen-rich carbon as a dual-catalyst for lithium-oxygen batteries. The achieved electrode with maximized exposed atomic active sites is beneficial for tailoring formation/decomposition mechanisms of uniformly distributed nano-sized lithium peroxide during oxygen reduction/evolution reactions due to abundant cobalt-nitrogen coordinate catalytic sites, thus demonstrating greatly enhanced redox kinetics and efficiently ameliorated over-potentials. Critically, theoretical simulations disclose that rich cobalt-nitrogen moieties as the driving force centers can drastically enhance the intrinsic affinity of intermediate species and thus fundamentally tune the evolution mechanism of the size and distribution of final lithium peroxide. In the lithium-oxygen battery, the electrode affords remarkably decreased charge/discharge polarization (0.40 V) and long-term cyclability (260 cycles at 400 mA g-1).

| S-EPMC7101366 | biostudies-literature

Nitric oxide is an obligate bacterial nitrification intermediate produced by hydroxylamine oxidoreductase.

Project description:Ammonia (NH3)-oxidizing bacteria (AOB) emit substantial amounts of nitric oxide (NO) and nitrous oxide (N2O), both of which contribute to the harmful environmental side effects of large-scale agriculture. The currently accepted model for AOB metabolism involves NH3 oxidation to nitrite (NO2-) via a single obligate intermediate, hydroxylamine (NH2OH). Within this model, the multiheme enzyme hydroxylamine oxidoreductase (HAO) catalyzes the four-electron oxidation of NH2OH to NO2- We provide evidence that HAO oxidizes NH2OH by only three electrons to NO under both anaerobic and aerobic conditions. NO2- observed in HAO activity assays is a nonenzymatic product resulting from the oxidation of NO by O2 under aerobic conditions. Our present study implies that aerobic NH3 oxidation by AOB occurs via two obligate intermediates, NH2OH and NO, necessitating a mediator of the third enzymatic step.

| S-EPMC5547625 | biostudies-literature

Atomically dispersed Fe atoms anchored on S and N-codoped carbon for efficient electrochemical denitrification.

Project description:Nitrate, a widespread contaminant in natural water, is a threat to ecological safety and human health. Although direct nitrate removal by electrochemical methods is efficient, the development of low-cost electrocatalysts with high reactivity remains challenging. Herein, bifunctional single-atom catalysts (SACs) were prepared with Cu or Fe active centers on an N-doped or S, N-codoped carbon basal plane for N2 or NH4+ production. The maximum nitrate removal capacity was 7,822 mg N ⋅ g-1 Fe, which was the highest among previous studies. A high ammonia Faradic efficiency (78.4%) was achieved at a low potential (-0.57 versus reversible hydrogen electrode), and the nitrogen selectivity was 100% on S-modified Fe SACs. Theoretical and experimental investigations of the S-doping charge-transfer effect revealed that strong metal-support interactions were beneficial for anchoring single atoms and enhancing cyclability. S-doping altered the coordination environment of single-atom centers and created numerous defects with higher conductivity, which played a key role in improving the catalyst activity. Moreover, interactions between defects and single-atom sites improved the catalytic performance. Thus, these findings offer an avenue for high active SAC design.

| S-EPMC8379959 | biostudies-literature

Atomically Dispersed Copper Sites in a Metal-Organic Framework for Reduction of Nitrogen Dioxide.

Project description:Metal-organic framework (MOF) materials provide an excellent platform to fabricate single-atom catalysts due to their structural diversity, intrinsic porosity, and designable functionality. However, the unambiguous identification of atomically dispersed metal sites and the elucidation of their role in catalysis are challenging due to limited methods of characterization and lack of direct structural information. Here, we report a comprehensive investigation of the structure and the role of atomically dispersed copper sites in UiO-66 for the catalytic reduction of NO2 at ambient temperature. The atomic dispersion of copper sites on UiO-66 is confirmed by high-angle annular dark-field scanning transmission electron microscopy, electron paramagnetic resonance spectroscopy, and inelastic neutron scattering, and their location is identified by neutron powder diffraction and solid-state nuclear magnetic resonance spectroscopy. The Cu/UiO-66 catalyst exhibits superior catalytic performance for the reduction of NO2 at 25 °C without the use of reductants. A selectivity of 88% for the formation of N2 at a 97% conversion of NO2 with a lifetime of >50 h and an unprecedented turnover frequency of 6.1 h-1 is achieved under nonthermal plasma activation. In situ and operando infrared, solid-state NMR, and EPR spectroscopy reveal the critical role of copper sites in the adsorption and activation of NO2 molecules, with the formation of {Cu(I)···NO} and {Cu···NO2} adducts promoting the conversion of NO2 to N2. This study will inspire the further design and study of new efficient single-atom catalysts for NO2 abatement via detailed unravelling of their role in catalysis.

| S-EPMC8323097 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data